What is "septin"

n. (context biochemistry English) Any of a class of proteins that have functions related to cytokinesis

Septins are a group of GTP-binding proteins found primarily in eukaryotic cells of fungi and animals, but also in some green algae. Different septins form protein complexes with each other. These complexes can further assemble into filaments, rings and gauzes. Assembled as such, septins function in cells by localizing other proteins, either by providing a scaffold to which proteins can attach, or by preventing diffusion of molecules from one compartment of the cell to another.

Septins have been implicated in the localization of cellular processes at the site of cell division, at the plasma membrane, at sites where specialized structures like cilia or flagella are attached to the cell body. In yeast cells, they compartmentalize parts of the cell and build scaffolding to provide structural support during cell division at the septum, from which they derive their name. Recent research in human cells suggests that septins build cages around bacterial pathogens, immobilizing the harmful microbes and preventing them from invading other cells.

As filament forming proteins, septins can be considered part of the cytoskeleton. Apart from forming non-polar filaments, septins associate with cell membranes, actin filaments and microtubules. Although present in most eukaryotes, septins have not been observed in plants.